• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.256-260
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• 2005

마그네슘은 자동차 엔진 경량화재료, 휴대폰케이스 등 기능성 경량재료로서의 용도개발과 함께 수요가 증가하고 있다. 마그네슘 제련법은 원료광의 특성에 따라 달라지는데 크게 용융염전해법과 열환원법 두 가지로 구분할 수 있다. 본 연구에서는 염화마그네슘을 사용하여 용융염전해법에 의해 전해 마그네슘을 얻고자 하였다. 전해전압 7V로 일정한 전극침지 깊이에서 두 가지 염욕을 비교 실험하였으며, $KCl/NaCl/MgCl_2$ 혼합 염욕을 $760^{\circ}C$에서 전해한 결과 약 47%의 전류효율을 달성할 수 있었다. 회수된 전해 마그네슘의 순도는 98% 이상이었다. 본 연구를 통하여 용융염 전해장치를 스케일엎하거나 상용화시에 장치설계 등에 필요한 기초 자료들을 축적할 수 있었다.

• Journal of radiological science and technology
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• v.21 no.2
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• pp.47-52
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• 1998

Tissue-equivalent $MgB_4O_7$ TL phosphors were prepared and the effects of Lantanides series activators on TLD properties of the phosphors were studied. The glow curve of TLD increased TL intensity and the peak temperature is low that is, the heating rate is $10^{\circ}C/sec$. The activation energy of the main peak estimated by the peak shape method. By these methods, the estimated activation energies were $0.76{\sim}1.55eV$ respectively. The TL phosphors prepared in this work may be utilized to radiation sensor elements because of this high sensitivity to X-ray.

• Journal of the Korean Solar Energy Society
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• v.21 no.2
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• pp.9-17
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• 2001

In this paper the attempts made by the authors to explore the feasibility of utilising concentrated solar beam radiation for joining engineering thermoplastics such as Acrylonitrilc/Butadiene/Styrene (ABS), Polycarbonate(PC) and Polymethylmethacrylate(PMMA) are presented. In addition, to study the joining of the materials, necessary experimentation with applying primer was performed. Tensile tests were conducted to determine the bond strength achieved at the specimen joint interface. Microscopic examinations of the fractured joints were performed in order to analyse the overall bond quality. Finally, the results in terms of bond strength achieved at the joint interface and energy consumed in the process were compared with those obtained with similar thermoplastic joining technique utilising microwave energy. In conclusion some advantages and limitations were outlined and necessary improvements of the jointing technique were recommended.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.1
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• pp.83-86
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• 2003

Mulberry plantations are prone to several kinds of insect pests including the thrips, Pesudodendrothrips mori. The thrips infestation affects the qualitative and quantitative characters of mulberry leaf, which in turn affects the silkworm cocoon crop. In the present study, four commercial insecticides viz., Rogor, Quinalphos, Confidor and Methyl parathion were tested for their efficacy in the control of P. mori thrips. These insecticides were observed to kill 68-80％ within 24 hrs in vivo and 100％ after 12 hrs post-treatment in vitro. Confidor (0.05％) and Quinalphos (0.2％) were most effective in controlling the thrips incidence. The insecticide-sprayed mulberry leaves did not show any adverse effect on the rearing of silkworms.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.3
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• pp.15-21
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• 1974

The information amount of monosyllables(characters) in Korean language is measured, in order of the following 3 steps. 1) The basic consonants and vowels are partitioned into two steps, 2) These set symbols, C and V, are sequentially combined to obtain the equation which represent the flow state of monosyllables. 3) From the equation, the state graphs can be constructed to examine the proferties of a stochastic process of monosyllables in Korean language. Furthermore, the entropy of Korean language by statistics is measured and compared with that of the western languages. The proposed methods are more definite, systematic, and simpler than the usual methods in examining the nature of information sources.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.14-20
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• 1998

Automatic finishing process requires the development of high efficient and precision abrasive machining method for dies and molds. This study describes the evaluation of the finishing characteristics, such as surfrace roughness, topography and material removal depth of the electrolytic mixed abrasive machining methods. Experimental setup is composed of 3 axis machining center, a newly developed finishing attachment with constant pressure, electrode and electrolytic bath. Finally, we achieved a successful result that surface roughness is $0.01\mu$m Ra and material removal depth is $120\mu$m using electrolytic(0.8A. 30V) mixed abrasive (#400 CBN, #320 SiC) machining method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.587-590
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• 2000

The new core making method economized on core sand requested. The new method is heating core box until it reaches reasonable temperature and then spraying core sand with core binder into core box. Inner temperature distribution have to uniform in order to form core of uniform thickness. Therefore, in this study we treat of inner temperature distribution of core box in priority. First, determine proper torch number. Next, optimize the torch position to minimize the average of absolute deviation(AVEDEV) of inner temperature. The results are as followed : 1. The torch number that makes inner temperature distribution about $300^\circ{C}$ uniformly is 25. 2. When $S_H$ and $S_V$ is 0.7, the torch position is optimized and AVEDEV is 5.85.

• YAKHAK HOEJI
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• v.35 no.2
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• pp.135-141
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• 1991

The general pharmacological tests with rhGM-CSF indicated that it had no influences on rotarod and locomotor activity tests, but shortened hexobarbital-sleeping time at the large dose of 3 mg/kg s.c. in mice. It elicited no hypothermic, analgesic and antiepileptic action. No influences on blood pressure and respiration in rabbits were observed at the dose of 1 mg/kg, i.v. and it did neither affect the receptors of adrenaline, acetylcholine, serotonin, histamine, kinin and oxytocin, nor antagonize the actions of histamine, serotonin and oxytocin at its concentrations of 1$\times$$10^{-6}$g/ml. However, this substance was demonstrated to stimulate the formation of leucocytes in rats.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.664-666
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• 2008

Low-temperature curable organic insulator was prepared through blending of polyimide type base resin and cross-linking agent. The newly developed resin can be formed into films using a wet process and cured at $130^{\circ}C$. Using the low temperature cured film as the gate dielectric layer, the field effect mobility of $0.15\;cm^2/V{\cdot}s$ was obtained from a pentacene field effect transistor in the saturation regime and no hysteresis behavior was observed in transfer curves.

• Speech Sciences
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• v.12 no.2
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• pp.7-16
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• 2005

The purpose, this experimental study was to identify pronunciation difficulties between male and female Korean speakers in their articulation of English vowels. Ten English mono-syllabic words were spoken six times by six male and six female college students. Formant frequencies were measured from sound spectrograms made by Pitch Works. Results show that Korean female speakers uttered English vowels more similar to those uttered by English native speakers than did Korean male speakers. While Korean male speakers could not readily distinguish between /i/ and /I/, /u/ and /v/, and /$\epsilon$/ and /ae/, respectively, Korean female speakers had difficulty only with /$\epsilon$/ and /ae/. The tentative results suggests that on the whole Korean speakers have difficulty in discriminating tense vowels from lax vowels, and they also have articulatory problems pronouncing low and back vowels such as /ae/. /a/ and /c/.